1. Field of the Invention
The present invention relates to a zoom lens and an image pickup device, and particularly to a technical field of a zoom lens that is suitable for a photographing optical system of a digital input-output device such as a digital still camera, a digital video camera or the like, which zoom lens is miniaturized and enhanced in performance, and which zoom lens is excellent in mass productivity, and an image pickup device using the zoom lens.
2. Description of the Related Art
Image pickup devices using a solid-state image pickup element such as a digital still camera and the like have recently been spread. With the spread of such image pickup devices such as a digital still camera and the like, even higher image quality is desired. In a digital still camera or the like, in particular, there is a desire for a photographing lens, especially a zoom lens, that has excellent image forming performance and which lens is compatible with a solid-state image pickup element having the large number of pixels.
In addition, there is a need for miniaturization in addition to higher image quality as described above, and there is also a need for a zoom lens that has low decentration sensitivity and which is excellent in mass productivity.
There are many kinds of zoom lenses for digital still cameras. However, as a lens type suitable for achieving a reduced size and a wider angle of view, a three-group zoom lens is known which zoom lens is formed by arranging a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power in order from an object side to an image side (see for example Japanese Patent Laid-Open Nos. 2002-244043, 2004-13169, 2007-286577, 2005-37727 and 2004-191599, hereinafter referred to as Patent Documents 1 to 5, respectively).
In a zoom lens described in Patent Document 1, a first lens group is formed by two lenses, that is, a negative lens and a positive lens, arranged in order from an object side to an image side.
In zoom lenses described in Patent Documents 2 to 5, a first lens group is formed by three lenses, that is, two negative lenses and one positive lens, arranged in order from an object side to an image side.